package com.my.chapter11;

import java.util.PriorityQueue;

public class practice29 {
    public static void main(String[] args) {
        PriorityQueue<P29> priorityQueue = new PriorityQueue<P29>();
        priorityQueue.add(new P29());
        priorityQueue.offer(new P29());//Error：P29 cannot be cast to java.lang.Comparable
    }
}

class P29{

}

